Artificial selection reveals complex genetic architecture of shoot branching and its response to nitrate supply in Arabidopsis.

Quantitative traits may be controlled by many loci, many alleles at each locus, and subject to genotype-by-environment interactions, making them difficult to map. One example of such a complex trait is shoot branching in the model plant Arabidopsis, and its plasticity in response to nitrate. Here, we use artificial selection under contrasting nitrate supplies to dissect the genetic architecture of this complex trait, where loci identified by association mapping failed to explain heritability estimates. We found a consistent response to selection for high branching, with correlated responses in other traits such as plasticity and flowering time. Genome-wide scans for selection and simulations suggest that at least tens of loci control this trait, with a distinct genetic architecture between low and high nitrate treatments. While signals of selection could be detected in the populations selected for high branching on low nitrate, there was very little overlap in the regions selected in three independent populations. Thus the regulatory network controlling shoot branching can be tuned in different ways to give similar phenotypes.

Structural connectivity in a paediatric case of anarchic hand syndrome.

BACKGROUND: "Anarchic hand" is a rare condition characterised by non-volitional, goal-directed movements of one arm. We report a case with analysis of structural and functional connectivity. CASE PRESENTATION: A 15 year old girl developed intermittent symptoms of intermanual conflict or anarchic hand as a result of traumatic brain injury during which she sustained a callosal bleed. Resting-state fMRI and DTI tractography were performed at a stage when symptoms had largely resolved. CONCLUSION: Structural connectivity between homologous superior frontal areas and functional connectivity between homologous posterior cingulate areas were significantly reduced, which may have contributed to causation. Tractography demonstrated new indirect connections between supplementary motor areas via the cerebellum, which we propose contributed to symptom resolution.

Motor and functional outcomes of a patient post-stroke following combined activity and impairment level training.

The purpose of this single-subject report was to determine the effect of a targeted training regimen aimed at improving motor and functional outcomes for a patient with chronic deficits after stroke. A 51-year-old woman with hemiparesis, 6 months post-stroke, participated in this prospective study. During the baseline, intervention, and immediate retention phases, performance was established by using repeated measures of four dependent variables: Fugl-Meyer assessment, Berg Balance Scale, 10-meter walk, and 6-minute walk. Two standard deviation band analyses were conducted on the four dependent variables with repeated measures. The Frenchay Activities Index and step length/single-limb support time measured at baseline and immediate retention were compared. During intervention, the participant was involved in a combined treatment protocol including body weight supported (BWS) treadmill training and strengthening exercises. Results indicated significant improvements in motor activity, balance, gait speed, and endurance. Progression was found in self-perceived participation. Although an improvement in step length symmetry occurred following training, a decrease in single-limb support time symmetry was found. BWS treadmill training, combined with strength training, significantly improved motor and functional performance in this participant with chronic deficits after stroke.